Animations

You can create very interactive applications with XSTEP. If you set the 'animate' variable to a non-zero value, animations can be created (in fact XSTEP will continuouslly generate broadcast events). You can control the speed of this animation with the function gettimeofday(), how in xstepgears application.

#include <xstep.h>

void draw(struct xtree *t) {

        if(!animate) return;

        XSetForeground(display,t->gc,rand()%256);
        XFillRectangle(display,t->win,t->gc,
                t->aw/2+rand()%t->aw-rand()%t->aw,
                t->ah/2+rand()%t->ah-rand()%t->ah,
                rand()%t->aw/4,rand()%t->ah/4);
}

void startf(struct xtree *t) { animate=1; }
void stopf (struct xtree *t) { animate=0; }

void xmain(int n,char *p[]) {

        struct xtree *win;

        win=window_create(0,0,400,180,"animation");
        win->broadcast=draw;

        button_create(-(2*80+8),-8,72,24,"start",       startf);
        button_create(-(1*80+8),-8,72,24,"stop",        stopf);
        button_create(-(0*80+8),-8,72,24,"close",       window_close);
}

In this example, the broadcast function of any widget (in this case a XSTEP window) can be redirected to other function (in this case draw()). The global variable 'animate' can enable or disable the continuous execution of draw().